This was made on purpose mainly for those two reasons :
Due to the pivot point you change the position of the belt (on the Z axis) while tensioning. It is currently designed to have a change of 0.03mm which is lower than belt tolerance and printed part tolerance. However, if y a user is opening too much the tensioner it could create too much difference in the position of the belt.
too much opening will make the idler less stiff and might become fragile
2.1 tensioner idler have small range for movement. I made small modification, range for open is now full. y_idler_tensioner-trimed-corner.zip
![IMG_1079](https://user-images.githubusercontent.com/47606742/72219582-ed652380-3547-11ea-83fe-0d7f2510ea0d.jpg)